Europe’s 80,000 sewage treatment plants offer considerable potential for an innovative, carbon-neutral process for the production of the universal chemical methanol.

That is according to ICODOS, a start-up founded at the Karlsruhe Institute of Technology (KIT), which alongside partners has built an innovative facility at Mannheim’s sewage treatment plant in Germany. The facility purifies the biogas produced by the plant and uses green hydrogen to convert it into carbon-neutral fuel for ships.

According to estimates by the International Maritime Organization, shipping accounts for approximately 3% of global greenhouse gas emissions. To reduce those emissions, environmentally friendly alternatives to conventional fossil fuels are urgently needed.

Operation of a demonstration plant that uses wastewater as a resource for the production of carbon-neutral methanol, a future marine fuel, started on 24 March 2025, with Dr Volker Wissing, Germany’s Federal Minister for Digital & Transport, pressing the start button. The other partners are the Institute for Micro Process Engineering and the Institute for Automation & Applied Informatics at KIT and the Wastewater Department of the City of Mannheim.

“We need to keep all of our technology options open in order to achieve our climate objectives," said Dr Wissing. "In addition to electrification and hydrogen propulsion, we need climate-friendly fuels for marine shipping in particular, and Germany should play a leading role in their research and development.

"That will be a growth market in the future. This is also about making our country independent from energy imports.

He continued, "Mannheim 001 shows how economic efficiency and climate action can go hand in hand. This project can serve as an example for many other locations in Germany and Europe.”

Professor Thomas Hirth, KIT’s vice-president for transfer and international affairs said, "This new facility is a striking demonstration of how research and entrepreneurship can lead to practical solutions for the successful transformation of our economy. The biogas it produces during wastewater treatment is a valuable resource.

"This is an innovative approach that shows how available resources can be used in a smart and climate-friendly way.”

Mannheim’s mayor, Christian Specht, said, “As a lighthouse project, Mannheim 001 is further proof that climate action and industrial growth can go hand in hand with new technologies.

"With support from Mannheim’s climate fund and in close cooperation with our wastewater department, it’s showing how a start-up from our Mafinex Technology Center can produce green fuel for the shipping industry. That’s another innovation made in Mannheim that we can be proud of.”

Innovative Process

The Mannheim 001 demonstration plant uses a patented process to convert biogas extracted from wastewater into carbon-neutral methanol. In the first stage, the biogas originating in the sewage treatment plant is purified.

The CO₂ it contains then reacts with green hydrogen to produce methanol, a versatile raw material that can be used in the chemical industry or as fuel for ships.

“With our technology, we can extract a high-quality energy carrier from an existing source,” said Dr Vidal Vazquez, co-founder of ICODOS. “Sewage plants could produce several million tonnes of renewable methanol per year in Germany alone.”

With its compact and scalable design, the partners say the process is ideal for distributed implementation. ICODOS is already in discussions with other sewage plant operators about building further production systems.

“Our current project shows the previously untapped potential of sewage plants as a core element of sustainable fuel production,” Vazquez said.